Bed furniture is known whose under-mattress have a so-called head part which can be fixed by means of a scissor-like notched mechanism in various inclined positions determined by the notching. In the case of this known design, continuous adjustment of the inclined position is not possible. Furthermore there is the even more inconvenient disadvantage that it is only possible to adjust and fix the desired angle of inclination by raising, i.e. moving upwards, the head part. Each time the head part is readjusted to a lower angle of inclination therefore it must--together with the mattress and pillows--first be raised to its highest position and then be lowered completely, after which the desired inclination may be chosen. As is known from experience, most people sleep alternately on their side and their back or stomach and each of these preferred sleeping positions correspond to a specific inclination of the head part so that ideally the latter should be adjusted several times a night. The fact that this periodic adjustment, i.e. adaptation to a new sleeping position, is not customary at present is due entirely to the deficiencies of the existing under-mattress designs.
A further drawback of the conventional head part design is the fact that the head part may only be progressively raised at an angle with respect to the remainder of the under-mattress, while the anatomical features of the intermediate area between the shoulder and the neck region are not taken into account. The result of this unfortunate state of affairs which is familiar to almost every person in the civilized world today is the continuous battle with the pillow in the restless search for a position of rest that will permit both the neck region and the shoulder muscles to relax at the same time.